From 16f4e56c75ac67e831ae7129b7a71984cda62732 Mon Sep 17 00:00:00 2001
From: "hyatt%netscape.com" <hyatt%netscape.com>
Date: Sat, 4 Mar 2000 12:00:35 +0000
Subject: [PATCH] Fix for 30369.  r=ben

---
 layout/xul/base/src/nsTreeRowGroupFrame.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/layout/xul/base/src/nsTreeRowGroupFrame.cpp b/layout/xul/base/src/nsTreeRowGroupFrame.cpp
index b852125e78a3..da0d61b8810e 100644
--- a/layout/xul/base/src/nsTreeRowGroupFrame.cpp
+++ b/layout/xul/base/src/nsTreeRowGroupFrame.cpp
@@ -1843,6 +1843,10 @@ nsTreeRowGroupFrame::GetCellFrameAtIndex(PRInt32 aRowIndex, PRInt32 aColIndex,
 #ifdef DEBUG_tree
   printf("Looking for cell (%d, %d)..", aRowIndex, aColIndex);
 #endif
+
+  // Init the result to null.
+  *aResult = nsnull;
+
   // The screen index = (aRowIndex - mCurrentIndex)
   PRInt32 screenIndex = aRowIndex - mCurrentIndex;
 
@@ -1858,7 +1862,7 @@ nsTreeRowGroupFrame::GetCellFrameAtIndex(PRInt32 aRowIndex, PRInt32 aColIndex,
   
   nsTableCellMap * cellMap = tableFrame->GetCellMap();
   CellData* cellData = cellMap->GetCellAt(screenIndex, aColIndex);
-  if (cellData->IsOrig()) { // the cell originates at (rowX, colX)
+  if (cellData && cellData->IsOrig()) { // the cell originates at (rowX, colX)
     cellFrame = cellData->GetCellFrame();
     if (cellFrame) { 
       *aResult = (nsTreeCellFrame*)cellFrame; // XXX I am evil.